Waterproof connection for spark plug terminals and the like



p 28, 1954 F. ELLIOTT 2,690,541

WATERPROOF CONNECTION FOR SPARK PLUG TERMINALS AND THE LIKE Filed April 14, 1950 Patented Sept. 28, 1954 WATERPROOF CONNECTION FOR SPARK PLUG TERMINALS AND THE LIKE Fred I. Elliott, Brockton, Mass, assignor of onehalf to Carleton S. Marden, Waltham, Mass.

Application April 14, 1950, Serial No. 155,986

8 Claims.

Although the connector may be used with various binding posts mounted on insulators or insulating studs it is particularly designed for connecting a high-voltage insulated ignition cable to the terminal post extending from a spark plug insulator.

One of the difficulties of connecting a high voltage cable to a terminal post lies in preventing an accumulation or condensation of moisture on the terminal post and insulator which will ground the high voltage delivered by the ignition cable and prevent the spark plug from firing. The moisture may be splashed on the plug or, even if the plug is enclosed, condense from air space inside the enclosure. Ordinary internal combustion engines in wet weather, and marine engines in any weather are difficult to start and subject to stalling or losing power when one or more of the spark plugs are so disabled. Many attempts have been made to manufacture a, device which will make a good electrical connection and at the same time moisture proof the insulator, at least adjacent the terminal post. Nevertheless previous devices have either failed adequately to seal the insulator or eliminate space for condensing moisture inside the sheath, or are of a complicated, expensive construction requiring special tools for attachment to the spark plug.

Objects of the present invention are, therefore, to provide a sheathed clip connector of extremely simplified and inexpensive manufacture, which makes a good electrical contact with a terminal post and at the same time dries, seals the terminal and its insulator from moisture, and encloses the same with substantially no air space thereabout from which moisture may condense. Another important object is to provide a sheathed connector which is easily connected to an insulated electrical cable, which is easily assembled and which may be manually attached to a terminal post and its insulator.

In one aspect the invention involves a connector for connecting a cable to a terminal post projecting out of an insulator, the connector comprising an elongate sheath of stiff rubberlike material having an opening at one end to receive said post, and within the sheath a spring clip for gripping said post and connecting it to said cable, the sheath having an annular rib in said opening, the outer edge of the rib seating on the end of said insulator when the connector is applied to the post and the spring clip abutting the inner edge of the rib to urge said outer edge against the insulator and afford a tight seal therebetween. Preferably the periphery of the rib fits the post closely thereby to form a tighter seal. In the preferred embodiment the rib is spaced inwardly from the mouth of the aforesaid opening and the intermediate portion of the sheath closely fits around the side of the insulator to form, an additional seal.

In another aspect the electrical connecting means preferably comprises a collar-type clip attached to the insulated cable and telescoping over the terminal post, the sheath comprising a body of rubber or the like having at one end a bore for receiving and enclosing the cable and at its other end another bore of lesser diameter than an insulator which wipes over the insulator, squeegeeing moisture therefrom and sealing the end of the insulator, the sheath having between the aforesaid bores an internal annular rib of lesser diameter than the above mentioned ter minal post for wiping the post free from moisture, one of the bores being of an inside diameter approximately the same as the corresponding dimension of the clip connector so that the connector and cable may be located in the sheath adjacent said shoulder by inserting the clip and cable through said bore.

It is desirable that the sheath be formed of a stiff rubber or rubber substitute having a hardness of 40 to on the standard rubber hardness scale.

In a further aspect the sheath includes a chamber between the annular rib and the bore which receives the cable, the chamber beingdimensioned to enclose the clip and firmly to position it axially of the other bore. Preferably the chamber has an abutment at one end opposing the annular rib at the other end, whereby the clip, once inserted in the chamber is held in a fixed position between the abutment and the rib.

The sheath may be straight or elbow-shaped. With a straight sleeve the two bores are axially aligned. With an elbow-shaped sleeve the axes of the bores intersect obliquely.

For the purpose of illustration a typical embodiment of the invention is illustrated in the accompanying drawings in which:

Fig. 1 is a sectional view of a. sheathed connector;

. 2 is a section of a sheath;

. 3 is a bottom view of the sheath; 4 is a side elevation of the sheath; 5 is an end view of a clip;

. 6 is a side elevation of a clip;

Fig. '7 is a sectional view showing the method of assembling a connector;

Fig. 8 is a sectional view of a modified connector and sheath;

Fig. 9 is a sectional view showing a modified method of assembly;

Fig. 10 is a sectional view of another modified sheath;

Fig. 11 is a sectional View of a connector assembled with the sheath shown in Fig. 10;

Fig. 12 is a sectional view of another modification;

Fig. 13 is an end plan view of a modified clip; and

Fig. 14. is a side elevation of the modified clip.

One type of connector embodying the present invention is shown in Figs. 1 to 7 of the drawings and includes an elbow-shaped sheath i for holding a helical spring clip 2 attached to an insulated ignition cable 3 and adapted to fit over the binding post 4 and insulator 5 of a spark plug l. The clip 2 comprises a coiled collar portion 8 designed to slide axially over the terminal post i and grip it tightly between the coils, and a hook 9 having a sharp end for piercing the insulation H of the cable 3 and making electrical contact with the wire 12 enclosed by the insulation. After passing through the insulation the end of the hook 9 is crimped over to hold the hook engaged with the cable. The length of the coil is approximately the same as the diameter of the cable to facilitate insertion of the cable and clip into the sheath I.

The sheath shown in Figs. 2 to 4 and '7 is molded from rubber or a rubber substitute such as Neoprene having a durometer hardness expressed in values of l0 to 60 on the rubber hardness scale and has a first bore i3 in one sleeve l3 and a second bore M in another sleeve 15 at right angles to the first sleeve. The first bore is slight- 1y less diameter than the external diameter of the cable 3, and the thickness and hardness of the walls of the sleeve [8 are sufficient to grip the cable tightly and seal the end of the cable enclosed therein from the entrance of moisture through the sleeve. The bore is enclosed in the sleeve i5 has a diameter somewhat less than than of the upper end of the insulator 5 of the spark plug. The first bore l3 terminates in a chamber is axially aligned with the second bore M and designed to enclose the clip tightly. Between the chamber l8 and the bore M is an annular shoulder or rib ll having a reduced bore IS. The inner diameter of the reduced bore 18 is likewise somewhat less than the diameter of the binding post 4.

As shown in Fig. 'l, after the collar 2 has been attached to the cable 3, the clip and cable may be inserted through the bore [3 until the clip seats in the chamber it. Since the length of the clip is sli htly greater than the diameter of the bore l3 it will, when inserted in the chamber, be held against radial movement by the rib [9 between the chamber and the bore l3. The inside diameter and the length of the chamber l6 are somewhat less than the corresponding dimensions of the collar clip so that the clip is positioned in the chamber under the compression of the sheath, the upper wall 2| of the chamber providing an abutment which presses the clip against the annular rib IT.

The assembled connector, including the sheath i and the clip 2, is applied to the spark plug '5 by telescoping the sleeve and clip over the binding post :3 and the upper end of the insulator 8. the connector is telescoped over the spark plug the sleeve is compresses around the insulator 6 and wipes or squeegees moisture from the insulator thus drying a portion at the upper end of the insulator. At the same time the annular shoulder i'. Squeegees over the binding post wiping the post free from moisture and drying it so that the surface contacted by the collar 2 will not be subject to corrosion. When fully telescoped over the terminal post, the clip 2 presses on the inner edge or abutment oi the annular rib ll thereby pressing the outer edge against the top of the insulator.

As previously mentioned all parts of the in sulator terminal post, clip and cable are held under compression by the sheath i so that practically no air space is left around the parts enclosed. Thus no moisture can condense from air space and corrode the terminal post or provide a path between the terminal post and the unenclosed portion of the insulator along which elec tric current may jump to grounded metal parts of the spark plug or the engine.

Figs. 8 and 9 show a modified embodiment of the sheath and connector in which the axis of the coil connector is disposed at right angles to the cable. In this embodiment the parts of the sleeve are alike with the exceptions that the chamber 56 is somewhat elongated to receive both the end of the cable 3 and a modified clip 2a in which the hook 9c is disposed at one end of the coil 8 rather than ofiset therefrom as shown in Fig. 6, and the shoulder l9 shown in Fig. 2 is omitted. This modified connector is assembled by passing the cable through the arm iii of the sheath la, through the chamber l6 and the other arm l5 until the end of the cable is exposed outside the sheath so that the modified clip 2a may be attached thereto. The cable is then withdrawn into the sheath, and the clip 2a swings about the modified hook 9a and seats with its axis at right angles to the cable as shown in Fig. 8.

With certain internal combustion engines it is preferable that the cable extend axially of the spark plug rather than at right angles as shown in Fig. 1. For this purpose a straight form of sheath, illustrated in Figs. 10 to 12, is provided. In the straight form of sheath the arms I01) and [5b and. the chamber 16b may be of the same general proportions as in the embodiment of Figs. 1 to '7, the bores 31) and Mb, however, are axially aligned with each other and with the chamber H61). An annular shoulder 21?; replaces the end wall Zl of Figs. 1 and 2. As shown in Fig. 11 the straight sheath lb receives and tightly clamps the cable in the arm liib with the clip 2a of the type like that shown in Fig. 9 enclosed in the chamber [51). The connector is then telescoped over the end of the spark plug as before with the arm [5b squeegeeing and sealing over the end of the insulator 8 and the shoulder or rib 57b wipin over and drying the binding post 4 and sealing against the top of the insulator under pressure of the clip.

In a further modification shown in Fig. 12 the annular portion I'll; or the shoulder Zlb of Fig. 10 may be replaced by a rubber ring 22 adapted to snap in an annular groove 23. The use of the ring 22 makes it possible to position the clip connector in the chamber [6b with less effort since the clip and cable can be inserted in the sleeve and the ring 22 thereafter snapped in place in the annular groove 23.

Figs. 13 and 14 illustrate a modified clip formed of a strip of spring metal with a hook 9b and a loop 8b. The loop 8b forms the collar adapted to telescope over the binding post of the spark plug similarly as the coil 8 of the clip shown in Figs. 5 and 6.

Whether the sheath be of the elbow type shown in Figs. 1 to 9 or the straight type shown in Figs. 10 to 12, the clip and cable may be inserted in the sheath either by the method illustrated in Fig. 7 or Fig. 9. The ring 22 and groove 23 may replace the annular shoulder ll shown in any of the embodiments.

A connector or sheath made according to the present invention not only provides a durable and good electrical connection which will not shake loose by vibration or impact but also will make a connection which virtually eliminates any possibility that a conducting path will be estab lished between the binding post and any grounded portion of the engine to which the spark plug is attached. The connector provides a connection which remains waterproof under the most adverse conditions, and which may actually be applied to the spark plug while the plug is immersed in water, the connector dryin the terminal post and upper end of the insulator in the process of application and sealing the terminal post as described above.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims. For example instead of slipping the sheath over the cable it may be molded around the cable.

I claim:

1. For connecting an electrical cable to a terminal post projecting from an insulator, a flexible sheath having a chamber with a cable opening to receive a cable and a post opening through which a post may be inserted, a spring clip substantially fitting said chamber for gripping said post, the diameter of one of said openings approximating the greatest dimension of the clip so that the clip may slide into the chamber through the opening whereby the clip may be connected to the cable before insertion into the sheath, preformed interior abutments at opposite ends of the chamber to position the clip endwise of the chamber, means for detachably connecting the clip to the end of a cable, and an integral skirt on the post-opening end of the sheath, the interior diameter of the skirt being smaller than that of the insulator but having sufficient elasticity to slide over the insulator, whereby the insulator is squeegeed by said skirt as the sheath is applied.

2. For connecting an electrical cable to a terminal post projecting from an insulator, a flexible sheath having a chamber with a cable opening to receive a cable and a post-opening through which a post may be inserted, a spring clip substantially fitting said chamber for gripping said post, the diameter of one of said openings approximating the greatest dimension of the clip so that the clip may slide into the chamber through the opening whereby the clip may be connected to the cable before insertion into the sheath, preformed interior abutments at opposite ends of the chamber to position the clip endwise of the chamber, means for detachably connecting the clip to the end of a cable, and an integral skirt on the post-opening end of the sheath, the internal diameter of the skirt being smaller than that of the insulator but having sufficient elasticity to slide over the insulator, the sheath having an integral flexible shoulder facing the open end of the skirt between said chamber and open end, the internal diameter of the shoulder being less than that of the post, whereby the insulator and post are squeegeed by said skirt and shoulder as the sheath is applied.

3. For connecting an electrical cable to a terminal post projecting from an insulator, a flexible sheath having a chamber with a cable opening to receive a cable and a post-opening through which a post may be inserted, a spring clip substantially fitting said chamber for gripping said post, the diameter of one of said openings approximating the greatest dimension of the clip so that the clip may slide into the chamber through the opening, means for detachably connecting the clip to the end of a cable, an integral skirt on the post-opening end of the sheath, an internal abutment at one end of the chamber to position the clip in one direction, and an internal preformed rib at the other end of the chamber, the side of the rib next to the chamber serving to position the clip in the direction opposite to said direction, the internal diameter of said rib being less than that of the post so that the side of the rib facing away from the chamber squeegees the post when the sheath is app-lied, and the internal diameter of the skirt being less than that of the insulator so that the skirt squeegees the insulator when the sheath is applied.

4. For connecting an electrical cable to a terminal post projecting from an insulator, a flexible sheath having a chamber with a cable opening to receive a cable and a post-opening through Which a post may be inserted, a spring clip shaped to gripsaid post and to fit the periphery of said chamber and to slide into the chamber through one of said openings, interior abutments at opposite ends of the chamber to position the clip endwise of the chamber, said clip having a hook extending transversely thereof upon which the end of the cable may be impaled, the length of the clip being confined approximately to the diameter of the cable opening so as not to interfere with the insertion of the clip into the sheath after the cable has been impaled on the hook, and an integral skirt on the post-opening end of the sheath, the internal diameter of the skirt being less than that of the insulator but having sufficient elasticity to slide over the insulator, whereby the clip may be connected to the cable before insertion into the sheath and the insulator is squeegeed by said skirt as the sheath is applied.

5. For connecting an electrical cable to a terminal post projecting from an insulator, an L shaped sheath of elastic material having a cable opening extending lengthwise of one leg and a post-opening extending lengthwise of the other leg and a clip chamber at the junction of the two openings, a coiled-spring clip removably fitting said chamber with its axis aligned with said postopening, and an interior shoulder facing the closed end of the post-opening for holding the clip in position, the shoulder being formed of said elas- 7, tic material integral with the sheath, said clip having a hook extending transversely thereof upon which the end of the cable may be impaled, the length of the clip being confined approximately to the diameter of the cable opening so as not to interfere with the insertion of the clip into the sheath after the cable has been impaled on the hook, the interior diameter of the postopening beyond said shoulder being less than that of the insulator so as to squeegee the insulator as the sheath is applied.

6. For connecting an electrical cable to a terminal post projecting from an insulator, an L- shaped sheath of elastic material having a cable opening extending lengthwise of one leg and a post-opening extending lengthwise of the other leg and a clip chamber at the junction of the two openings, a coiled-spring clip removably fitting said chamber with its axis aligned with said post-opening, an internal abutment at one end of the chamber to position the clip in one direction, and an internal rib at the other end of the chamber, the side of the rib next to the chamber serving to position the clip in the direction opposite to said direction, the rib being formed of said elastic material integral with the sheath, said clip having a hook extending transversely thereof upon which the end of the cable may be impaled, the length of the clip being confined approximately to the diameter of the cable opening so as not to interfere with the insertion of the clip into the sheath after the cable has been impaled on the hook, the internal diameter of said rib being less than that of the post so as to squeegee the post as the sheath is applied to the post, an integral skirt on the post-opening end of the sheath, the internal diameter of the skirt being less than that of the insulator so as to squeegee the insulator when the sheath is applied, the diameters of said openings approximating each other, the length and diameter of said chamber approximating said diameters, and the length and diameter of the clip approximating each other, whereby the clip may be connected to the cable before insertion into the sheath and the clip fits the chamber snugly after insertion.

7. For connecting an electrical cable to a terminal post extending from an insulator, a resilient sheath having a chamber, a cable opening to receive a cable, a post opening through which a post may be inserted, said openings communicating with said chamber, a spring clip substantially fitting said chamber for gripping said post, means for attaching the clip to a cable, the diameter of one of said openings approximating the greatest dimension of the clip so that the clip may slide into said chamber through the opening, a preformed internal annular rib in said post opening extending over one end of said clip, an interior abutment in said chamber opposite said rib, said rib having an inner face, said abutment being spaced from said inner face the depth of the clip to confine the clip between said abutment and inner face, and said rib having an outer face adapted to be pressed by said clip against said insulator when the clip grips said post.

8. A sleeve for receiving a cable carrying a spring clip at the end thereof and for fitting over a terminal post extending from an insulator, comprising a unitary body of resilient material, means within said body forming a chamber with opposed abutments spaced to position said clip Within the chamber, one of said abutments comprising the inner face of a preformed annular rib of internal diameter to snugly receive said terminal post, said annular rib having an outwardly directed face adapted to be sealed against said insulator.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,376,844 Weber May 3, 1921 1,912,980 Hoogendorn June 6, 1933 2,436,712 Burrell et al. Feb. 24, 1948 2,480,545 Burrell Aug. 30, 1949 2,550,358 LeGrand et a1. Apr. 24, 1951 2,553,114 Sailler May 15, 1951 FOREIGN PATENTS Number Country Date 335,312 Italy Feb. 4, 1936 510,189 France Aug. 31, 1920 

